Multi-platform for OpenGL demo. GLFW+GLAD

glfwTest.cpp

#include <iostream>
//#define GLFW_INCLUDE_NONE
#include <glad/glad.h>
#include <GLFW/glfw3.h>

int main()
{
    GLFWwindow* window;

    /* Initialize the library */
    if (!glfwInit())
        return -1;

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }

    /* Make the window's context current */
    glfwMakeContextCurrent(window);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    // get version info
    const GLubyte* renderer = glGetString(GL_RENDERER); // get renderer string
    const GLubyte* version = glGetString(GL_VERSION); // version as a string
    printf("Renderer: %s\n", renderer);
    printf("OpenGL version supported %s\n", version);


    float points[] = {
       0.0f,  0.5f,  0.0f,
       0.5f, -0.5f,  0.0f,
      -0.5f, -0.5f,  0.0f
    };

    GLuint vbo = 0;
    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, 9 * sizeof(float), points, GL_STATIC_DRAW);

    GLuint vao = 0;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);


    const char* vertex_shader =
        "#version 100\n"
        "attribute vec3 vp;"
        "void main() {"
        "  gl_Position = vec4(vp, 1.0);"
        "}";

    const char* fragment_shader =
        "#version 100\n"
        "void main() {"
        "  gl_FragColor = vec4(0.5, 0.0, 0.5, 1.0);"
        "}";

    GLuint vs = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vs, 1, &vertex_shader, NULL);
    glCompileShader(vs);

    GLint vertex_compiled;
    glGetShaderiv(vs, GL_COMPILE_STATUS, &vertex_compiled);
    if (vertex_compiled != GL_TRUE)
    {
        GLsizei log_length = 0;
        GLchar message[1024];
        glGetShaderInfoLog(vs, 1024, &log_length, message);
        // Write the error to a log
        printf("vertex_compiled: %s\n", message);
    }


    GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fs, 1, &fragment_shader, NULL);
    glCompileShader(fs);

    GLint fragment_compiled;
    glGetShaderiv(fs, GL_COMPILE_STATUS, &fragment_compiled);
    if (fragment_compiled != GL_TRUE)
    {
        GLsizei log_length = 0;
        GLchar message[1024];
        glGetShaderInfoLog(fs, 1024, &log_length, message);
        // Write the error to a log
        printf("fragment_compiled: %s\n", message);
    }


    GLuint shader_programme = glCreateProgram();
    glAttachShader(shader_programme, fs);
    glAttachShader(shader_programme, vs);
    glLinkProgram(shader_programme);

    /* Loop until the user closes the window */
    while (!glfwWindowShouldClose(window))
    {
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
        glUseProgram(shader_programme);
        glBindVertexArray(vao);
        // draw points 0-3 from the currently bound VAO with current in-use shader
        glDrawArrays(GL_TRIANGLES, 0, 3);
        // update other events like input handling 
        glfwPollEvents();
        // put the stuff we've been drawing onto the display
        glfwSwapBuffers(window);
    }

    glfwTerminate();
    return 0;
}

shader改用 webgl/GLES2.0 的#100版本